Reaction of neodymium with air
Neodymium tarnishes slowly in air, and burns readily, forming neodymium(III) oxide, Nd2O3.
4 Nd(s) + 3 O2(g) 2 Nd2O3(s)
Reaction of neodymium with acids
Neodymium dissolves readily in dilute sulphuric acid, forming lilac Lu(III) ions and hydrogen gas, H2.
2 Nd(s) + 3 H2SO4(aq) 2 Nd3+(aq) + 3 SO42−(aq) + 3 H2(g)
Reaction of neodymium with halogens
Neodymium reacts with all the halogens, forming the corresponding neodymium(III) halides.
2 Nd(s) + 3 F2(g) 2 NdF3(s) [violet]
2 Nd(s) + 3 Cl2(g) 2 NdCl3(s) [mauve]
2 Nd(s) + 3 Br2(g) 2 NdBr3(s) [violet]
2 Nd(s) + 3 I2(g) 2 NdI3(s) [green]
Reaction of neodymium with water
Neodymium reacts slowly with cold water, and quickly with hot water, forming neodymium(III) hydroxide, Nd(OH)3, and hydrogen gas (H2).
2 Nd(s) + 6 H2O(l) 2 Nd(OH)3(aq) + 3 H2(g)